Willemite is a Zinc Silicate which is famously known for two things. It is very commonly strongly fluorescent, and, it comes in an array of uniquely aesthetic structures from fibrous needles to articulate large Trigonal crystals. Willemite is one of the three members of the Phenakite group.
Many of the finest Willemite are noted to come from the Tsumeb Mine in Namibia. The locality has produced fine and well formed botryoidal formations of apple green and more rarely blue colours.
What to look for: Luster, Color, Isolation and Formation of Crystals, Associations, Specimens on Matrix, and Unusual Localities.